A CONCISE INTRODUCTION TO LOGIC
EXAM SCRIPT UPDATED QUESTIONS AND
ACCURATE ANSWERS FULL SOLUTION
●● a fallacy can be:
Answer: unsound or uncogent
●● if an argument is unsound or uncogent....
Answer: it has one or more false premises or it contains a fallacy (or
both)
●● an unsound argument
Answer: a deductive argument that is invalid, has one or more false
premises, or both
●● formal fallacy
Answer: a fallacy that may be identified by merely examining the form
or structure of an argument (found only in deductive arguments that
have identifiable forms)
●● formal fallacy of a categorical syllogism:
Answer: All bullfights are grotesque rituals.
All executions are grotesque rituals.
,Therefore, all bullfights are executions.
All A are B.
All C are B.
______
All A are C.
(If the letters C and B are interchanged, the form becomes valid, and the
original argument, with the same change introduced, also becomes valid
(but unsound).)
●● formal fallacy of a hypothetical syllogism:
Answer: If apes are intelligent, then apes can solve puzzles.
Apes can solve puzzles.
Therefore, apes are intelligent.
If A then B.
B.
_______
A.
, (In this case, if A and B are interchanged in the first premise, the form
becomes valid, and the original argument, with the same change, also
becomes valid.)
●● informal fallacies are arguments that can be detected only by....
Answer: examining the content of an argument
(The Brooklyn Bridge is made of atoms.
Atoms are invisible.
__________
Therefore, the Brooklyn Bridge is invisible.
To detect this fallacy one must know something about bridges—namely,
that they are large visible objects, and even though their atomic
components are invisible, this does not mean that the bridges themselves
are invisible.)
●● If Rasputin was really mad, then he deceived Czar Nicholas II.
Rasputin was not really mad. Therefore, he did not deceive Czar
Nicholas II.
Formal or informal fallacy?
Answer: formal fallacy
EXAM SCRIPT UPDATED QUESTIONS AND
ACCURATE ANSWERS FULL SOLUTION
●● a fallacy can be:
Answer: unsound or uncogent
●● if an argument is unsound or uncogent....
Answer: it has one or more false premises or it contains a fallacy (or
both)
●● an unsound argument
Answer: a deductive argument that is invalid, has one or more false
premises, or both
●● formal fallacy
Answer: a fallacy that may be identified by merely examining the form
or structure of an argument (found only in deductive arguments that
have identifiable forms)
●● formal fallacy of a categorical syllogism:
Answer: All bullfights are grotesque rituals.
All executions are grotesque rituals.
,Therefore, all bullfights are executions.
All A are B.
All C are B.
______
All A are C.
(If the letters C and B are interchanged, the form becomes valid, and the
original argument, with the same change introduced, also becomes valid
(but unsound).)
●● formal fallacy of a hypothetical syllogism:
Answer: If apes are intelligent, then apes can solve puzzles.
Apes can solve puzzles.
Therefore, apes are intelligent.
If A then B.
B.
_______
A.
, (In this case, if A and B are interchanged in the first premise, the form
becomes valid, and the original argument, with the same change, also
becomes valid.)
●● informal fallacies are arguments that can be detected only by....
Answer: examining the content of an argument
(The Brooklyn Bridge is made of atoms.
Atoms are invisible.
__________
Therefore, the Brooklyn Bridge is invisible.
To detect this fallacy one must know something about bridges—namely,
that they are large visible objects, and even though their atomic
components are invisible, this does not mean that the bridges themselves
are invisible.)
●● If Rasputin was really mad, then he deceived Czar Nicholas II.
Rasputin was not really mad. Therefore, he did not deceive Czar
Nicholas II.
Formal or informal fallacy?
Answer: formal fallacy
